In the past, most "junk silver" coins on eBay often sell between a +/- 5% spread of the melt value. For example, if you have a silver coin that has a $1.00 melt value, you should be able to find someone who's willing to buy/sell it between $0.95 - $1.05. However, the recent spike in the silver price has caused premiums to fluctuate wildly.

If you're planning to buy/sell 1 Washington quarter(s) when silver is priced at $14.79
/ ounce, the final total may fall between $2.54 - $2.81 on eBay.

eBay Auctions (1932-1964 Washington Quarter Listings Only):

I believe that the old saying, "A coin is only worth what someone will pay for it," is absolutely true. I like eBay because it displays what people are actually paying for coins. Monthly coin price magazines and online price lists may not reflect current market conditions because they don't demonstrate what people are actually willing to pay.